The present invention relates to a method and system for delivering a pressurized fluid, such as hydrogen or another compressed gas, to a receiving tank, such as a vehicle fuel tank, and in particular the invention relates to a self-powered mobile fueling station for delivering a fuel (e.g., hydrogen) at pressures of 5,000 psig or greater to fuel tanks of vehicles, such as hydrogen-powered vehicles.
Although the invention is discussed herein with regard to delivery of pressurized hydrogen gas to fuel tanks of hydrogen-powered vehicles, persons skilled in the art will recognize that the invention has other applications. For example, it may be used to deliver other pressurized fluids which may or may not be used as fuels, and the pressurized fluids may be delivered to various types of receiving tanks other than vehicle fuel tanks.
With the increasing interest in clean and efficient fuels, automobile manufacturers are designing and manufacturing hydrogen-powered vehicles that are powered by fuel cells or hydrogen internal combustion engines. Hydrogen is being tested in these vehicles and has the potential to be the fuel of choice in the future.
These hydrogen-powered vehicles are in the development stage and manufacturers are performing extensive tests to improve the vehicles and related technologies. Since there is not an established hydrogen fueling infrastructure in place, some manufacturers are installing fixed hydrogen fueling stations at test sites and elsewhere. Testing is taking place throughout North America without sufficient capability to fuel the test vehicles away from the fixed hydrogen fueling stations.
Hydrogen-powered vehicles are also being demonstrated and promoted at public events to increase consumer awareness and interest. These events are taking place at many locations where hydrogen fueling is needed but is not available. Currently, hydrogen is delivered to these events in the form of liquid or as a cylinder product.
BX cylinders, individually or in packs, are typically used to provide hydrogen to customers. However, these cylinders are very heavy and difficult (expensive) to transport.
In view of the above, there is a need for mobile hydrogen fueling stations to fuel test vehicles and demonstration vehicles at public events. Mobile hydrogen fueling stations also could be used for maintaining small fleets of hydrogen-powered vehicles, providing fuel for emergency roadside assistance, and for fueling stationary fuel cells or hydrogen-powered facilities at remote sites.
Powertech Labs and Dynatek, Inc. have offered for sale a mobile fueling station that is believed to have a supply pressure of 3,600 psig.
There exists a void in the availability of fuel for hydrogen-powered vehicles. Government and industry demonstration projects are hampered by the inability to fuel the prototype vehicles being tested and demonstrated.
In view of the current needs of industry and government programs, a mobile hydrogen fueling station is needed. Preferably, such a station should be a self-contained, self-powered, mobile fueling station capable of delivering high pressure gas (e.g., at pressures of 5,000 psig or more) in an optimal manner (e.g., minimal fueling time and maximum usage of the fuel carried by the mobile fueling station so as to minimize the need to refill the station).
As used herein, the term xe2x80x9cself-containedxe2x80x9d means that the power needed to actuate valves, deliver compressed gas at maximum pressure and at maximum rates, provide communications between the fueling station and a vehicle to be filled, and provide communications between the fueling station and a remote monitor is inherent in the fueling station. The term xe2x80x9cself-poweredxe2x80x9d means that no external electric power or other external utilities are needed to operate the fueling functions of the mobile fueling station.
Although the prior art includes various types of mobile fueling stations, none of these stations satisfy the current needs. For example, U.S. Pat. Nos. 5,983,962 and 3,257,031 each disclose a mobile fueling station. However, these patents do not teach how to deliver high-pressure hydrogen in an optimal manner.
Other patents and publications also disclose mobile delivery stations for storing and dispensing fuel, but these stations are not self-powered and are not designed to deliver high-pressure hydrogen in an optimal manner. See for example, U.S. Pat. Nos. 5,887,567 and 5,682,750. See also U.S. patent application Ser. No. 2002/0046773 and International Publication WO 98/52677.
U.S. Pat. No. 5,596,501 discloses a system for dispensing fuel at remote locations and a method of operating same. However, it does not teach a mobile self-contained delivery station for delivering high-pressure hydrogen in an optimal manner.
The present invention teaches delivery of high-pressure hydrogen in a cascading manner to optimize fueling time. Although the prior art does disclose cascading (e.g., U.S. Pat. Nos. 5,673,735 and 5,810,058), it does not disclose cascading delivery in an optimal manner (e.g., to provide an optimal rate of fill) for use in a self-powered, self-contained mobile hydrogen fueling station.
U.S. patent application Ser. No. 2002/0014277 discloses an apparatus and method for filling a tank with hydrogen gas. However, it does not address the problems involved with filling tanks or storage vessels of various sizes.
It is desired to have an improved method and system for delivering a pressurized fluid, such as hydrogen gas, to a receiving tank, such as a vehicle fuel tank. It is further desired to have a method and system to allow for the fueling of hydrogen-powered vehicles in areas where there is no hydrogen infrastructure (pipeline, plants, filling stations, etc.).
It is still further desired to have a self-contained mobile fueling station which can be deployed anywhere and provide fuel, such as hydrogen, to vehicle demonstration projects on an efficient, economical basis.
It is still further desired to have an automatic method and system to safely store and dispense hydrogen gas at different pressures, making it possible to fuel a vehicle rated for 5,000 psig or more without the use of a compressor.
It is still further desired to have a self-powered mobile hydrogen fueling station to support hydrogen demonstration projects and small hydrogen-powered vehicle fleets without the use of external electric power or other external utilities.
It is still further desired to have a self-powered mobile hydrogen fueling station which also may be used to provide emergency roadside assistance to hydrogen-powered vehicles and/or to stationary fuel cells or hydrogen-powered facilities at remote locations.
It is still further desired to have an improved method and system for controlling the rate of delivery of a pressurized fluid, such as hydrogen gas, to a receiving tank, such as a vehicle fuel tank.
It also is desired to have a method and system for delivering a pressurized fluid, such as a hydrogen fuel, at a controlled rate of delivery to receiving tanks of various sizes, such as vehicle fuel tanks, which afford better performance than the prior art, and which also overcome many of the difficulties and disadvantages of the prior art to provide better and more advantageous results.
The present invention is a self-powered station and a method for delivering a pressurized fluid from the self-powered station to a receiving tank without using mechanical compression, external electric power, or other external utilities. The invention also includes an apparatus and method for controlling a rate of delivery of a pressurized fluid from a storage vessel to a receiving tank through a conduit in fluid communication with the storage vessel and the receiving tank.
A first embodiment of the self-powered station has a plurality of vessels, including a first vessel containing a first quantity of the pressurized fluid at a first pressure and a second vessel containing a second quantity of the pressurized fluid at a second pressure. The station also includes: a conduit having a first end in fluid communication with a first receiving tank and a second end in controllable fluid communication with each of the first vessel and the second vessel; means for transferring at least a portion of the first quantity of the pressurized fluid from the first vessel through the conduit to the first receiving tank without using mechanical compression, external electric power, or other external utilities, thereby resulting in an increasing pressure in the first receiving tank and a decreasing pressure in the first vessel, the increasing pressure in the first receiving tank being less than the second pressure of the pressurized fluid in the second vessel; means for measuring continuously a pressure differential between the increasing pressure in the first receiving tank and the decreasing pressure in the first vessel; means for discontinuing the transfer of the pressurized fluid from the first vessel when a predetermined limit value is reached; and means for transferring at least a portion of the second quantity of the pressurized fluid from the second vessel through the conduit to the first receiving tank without using mechanical compression, external electric power, or other external utilities.
There are several variations of the first embodiment of the self-powered station. In one variation, the pressurized fluid is a gas. In another variation, the pressurized fluid is hydrogen. In another variation, the limit value of the pressure differential is zero. In yet another variation, the first receiving tank is a vehicle storage tank.
A second embodiment of the self-powered station is similar to the first embodiment but includes means for moving the self-powered station from the first location near the first receiving tank to a second location near a second receiving tank.
A third embodiment of the self-powered station is similar to the first embodiment but includes an insulation material disposed between the first or second vessel and a vessel adjacent the first or second vessel.
A fourth embodiment of the self-powered station is similar to the first embodiment but includes a gas-permeable roof adapted to vent the pressurized fluid in a gaseous state.
The fifth embodiment of the self-powered station is similar to the first embodiment but includes the following additional elements: means for determining when the plurality of vessels are empty or near empty; means for monitoring the self-powered station from a monitor in a remote location; and means for reporting to the monitor from the sell-powered station a determination that the plurality of vessels are empty or near empty.
A sixth embodiment is an automated mobile self-contained self-powered station having a plurality of vessels for delivering a pressurized hydrogen gas at 5,000 psig or greater to a first hydrogen-powered vehicle fuel storage tank without using mechanical compression, external electric power, or other external utilities. The station includes a first vessel containing a first quantity of the pressurized hydrogen gas at a first pressure, and a second vessel containing a second quantity of the pressurized hydrogen gas at a second pressure. The station also includes: a conduit having a first end in fluid communication with the first hydrogen-powered vehicle fuel storage tank and a second end in controllable fluid communication with each of the first vessel and the second vessel; means for transferring at least a portion of the first quantity of the pressurized hydrogen gas from the first vessel through the conduit to the first hydrogen-powered vehicle fuel storage tank without using mechanical compression, external electric power, or other external utilities, thereby resulting in an increasing pressure in the first hydrogen-powered vehicle fuel storage tank and a decreasing pressure in the first vessel, the increasing pressure in the first hydrogen-powered vehicle fuel storage tank being less than the second pressure of the pressurized hydrogen gas in the second vessel; means for measuring continuously a pressure differential between the increasing pressure in the first hydrogen-powered vehicle fuel storage tank and the decreasing pressure in the first vessel: means for discontinuing the transfer of the pressurized hydrogen gas from the first vessel when a predetermined limit value is reached; means for transferring at least a portion of the second quantity of the pressurized hydrogen gas from the second vessel through the conduit to the first hydrogen-powered vehicle fuel storage tank without using mechanical compression, external electric power, or other external utilities; means for moving the mobile self-contained self-powered station from a first location near the first hydrogen-powered vehicle fuel storage tank to a second location near a second hydrogen-powered vehicle fuel storage tank; means for determining when the plurality of vessels are empty or near empty; means for monitoring the mobile self-contained self-powered station from a monitor in a remote location; and means for reporting to the monitor from the mobile self-contained self-powered station a determination that the plurality of vessels are empty or near empty.
The present invention also includes an apparatus for controlling a rate of delivery of a pressurized fluid from a storage vessel to a receiving tank through a conduit in fluid communication with the storage vessel and the receiving tank. The apparatus includes: means for establishing a predetermined rate of pressure rise to be maintained during a predetermined time period for filling of the receiving tank with the pressurized fluid; and means for maintaining the predetermined rate of pressure rise during filling of the receiving tank with the pressurized fluid during the predetermined time period.
There are several variations of the apparatus. In one variation, the means for establishing a predetermined rate of pressure rise includes a computer/controller for generating an electrical signal convertible to a low pressure gas signal, and a regulator for amplifying the low pressure gas signal and controlling a fill pressure in the receiving tank.
In another variation, the means for maintaining the predetermined rate of pressure rise includes: a pressure control device in communication with the conduit or another conduit through which the pressurized fluid flows at an actual pressure before entering the receiving tank, the pressure control device adapted to increase or decrease the actual pressure of the pressurized fluid; means for calculating periodically a rate of pressure rise over time; and means for commanding the pressure control device to decrease the actual pressure when the rate of pressure rise is greater than the established predetermined rate of pressure rise, and to increase the actual pressure when the rate of pressure rise is less than the established predetermined rate of pressure rise.
In yet another variation of the apparatus, the rate of delivery is controlled as a function of either a percentage of a designated target pressure already achieved or a percentage of a designated target pressure yet to be achieved during a remaining portion of the predetermined time period. In a variant of this variation, the function is linear. In another variant, the function is geometric. In yet another variant, the receiving tank has an instantaneous thermodynamic state where the function varies over time with any changes in the instantaneous thermodynamic state to provide an optimal rate of fill.
Another embodiment is an apparatus for controlling a rate of delivery of a pressurized hydrogen gas at 5,000 psig or greater from at least one storage vessel to a hydrogen-powered vehicle storage tank through a conduit in fluid communication with the at least one storage vessel and the hydrogen-powered vehicle storage tank. This embodiment includes: means for establishing a predetermined rate of pressure rise to be maintained during a predetermined time period for filling of the hydrogen-powered vehicle fuel storage tank with the pressurized hydrogen gas, comprising a computer/controller for generating an electric signal convertible to a low pressure gas signal, and a regulator for amplifying the low pressure gas signal and controlling a fill pressure in the receiving tank; means for maintaining the predetermined rate of pressure rise during filling of the hydrogen-powered vehicle fuel storage tank with the pressurized hydrogen gas during the predetermined time period, comprising a pressure control device in communication with the conduit or another conduit through which the pressurized hydrogen gas flows at an actual pressure before entering the hydrogen-powered vehicle fuel storage tank, the pressure control device adapted to increase or decrease the actual pressure of the pressurized hydrogen gas, means for calculating periodically a rate of pressure rise over time, and means for commanding the pressure control device to decrease the actual pressure when the rate of pressure rise is greater than the established predetermined rate of pressure rise, and to increase the actual pressure when the rate of pressure rise is less than the established predetermined rate of pressure rise, wherein the rate of delivery is controlled as a function of either a percentage of a designated target pressure already achieved or a percentage of a designated target pressure yet to be achieved during a remaining portion of the predetermined time period.
The present invention also includes a method for delivering a pressurized fluid from a self-powered station to a first receiving tank without using mechanical compression, external electric power, or other external utilities, the self-powered station having a plurality of vessels, including at least a first vessel containing a first quantity of the pressurized fluid at a first pressure and a second vessel containing a second quantity of the pressurized fluid at a second pressure. There are several embodiments and variations of the method. The first embodiment includes multiple steps. The first step is to provide a conduit having a first end and a second end in controllable fluid communication with each of the first vessel and the second vessel. The second step is to place the first end of the conduit in fluid communication with the first receiving tank. The third step is to transfer at least a portion of the first quantity of the pressurized fluid from the first vessel through the conduit to the first receiving tank without using mechanical compression, external electric power, or other external utilities, thereby resulting in an increasing pressure in the first receiving tank and a decreasing pressure in the first vessel, the increasing pressure in the first receiving tank being less than the second pressure of the pressurized fluid in the second vessel. The fourth step is to measure continuously a pressure differential between the increasing pressure and the first receiving tank and the decreasing pressure in the first vessel. The fifth step is to designate a limit value of the pressure differential at which a transfer of the pressurized fluid from the first vessel to the first receiving tank is to be discontinued. The fifth step is to designate a limit value of the pressure differential at which a transfer of the pressurized fluid from the first vessel to the first receiving tank is to be discontinued. The sixth step is to discontinue the transfer of the pressurized fluid from the first vessel when the limit value is reached. The seventh step is to transfer at least a portion of the second quantity of the pressurized fluid from the second vessel through the conduit to the first receiving tank without using mechanical compression, external electric power, or other external utilities.
There are several variations of the first embodiment of the method. In one variation, the first receiving tank is a vehicle fuel storage tank. In another variation, the pressurized fluid is a gas. In another variation, the pressurized fluid is hydrogen. In yet another variation, the limit value of the pressure differential is zero.
A second embodiment of the method is similar to the first embodiment of the method but includes an additional step. In the second embodiment, the self-powered station is mobile or portable and the additional step is to move the self-powered station from a first location near the first receiving tank to a second location near a second receiving tank.
A third embodiment is an automated method for delivering a pressurized hydrogen gas at 5,000 psig or greater from a mobile self-contained self-powered station to a first hydrogen-powered vehicle fuel storage tank without using mechanical compression, external electric power, or other external utilities, the self-powered station having a plurality of vessels, including at least a first vessel containing a first quantity of the pressurized hydrogen gas at a first pressure and a second vessel containing a second quantity of the pressurized hydrogen gas at a second pressure. The automated method includes multiple steps. The first step is to provide a conduit having a first end and a second end in controllable fluid communication with each of the first vessel and the second vessel. The second step is to place the first end of the conduit in fluid communication with the first hydrogen-powered vehicle fuel storage tank. The third step is to transfer at least a portion of the first quantity of the pressurized hydrogen gas from the first vessel through the conduit to the first hydrogen-powered vehicle fuel storage tank without using mechanical compression, external electric power, or other external utilities, thereby resulting in an increasing pressure in the first hydrogen-powered vehicle fuel storage tank and a decreasing pressure in the first vessel, the increasing pressure in the first hydrogen-powered vehicle fuel storage tank being less than the second pressure of the pressurized hydrogen gas in the second vessel. The fourth step is to measure continuously a pressure differential between the increasing pressure in the first hydrogen-powered vehicle fuel storage tank and the decreasing pressure in the first vessel. The fifth step is to designate a limit value of the pressure differential at which a transfer of the first pressurized hydrogen gas from the first vessel to the first hydrogen-powered vehicle fuel storage tank is to be discontinued. The sixth step is to discontinue the transfer of the pressurized hydrogen gas from the first vessel when the limit value is reached. The seventh step is to transfer at least a portion of the second quantity of the pressurized hydrogen gas from the second vessel through the conduit to the first hydrogen-powered vehicle fuel storage tank without using mechanical compression, external electric power, or other external utilities. The eighth step is to move the mobile self-contained self-powered station from a first location near the first hydrogen-powered vehicle storage tank to a second location near a second hydrogen-powered vehicle fuel storage tank.
A fourth embodiment is a method for delivering a pressurized fluid from a self powered station to at least one receiving tank without using mechanical compression, electric power, or other external utilities, the self-powered station having n+1 vessels, wherein n is an integer greater than zero, each vessel containing a quantity of the pressurized fluid having a pressure which decreases as the quantity decreases. This fourth embodiment of the method includes the following steps: (a) providing a conduit having a first end and a second end in controllable fluid communication with each of the vessels; (b) selecting the receiving tank to receive the pressurized fluid; (c) engaging the first end of the conduit in fluid communication with the selected receiving tank, the selected receiving tank having a pressure which increases as the quantity of pressurized fluid is delivered to the selected receiving tank; (d) selecting a vessel presently containing a quantity of pressurized fluid at a pressure greater than a present pressure of the pressurized fluid in the selected receiving tank; (e) transferring at least a portion of the quantity of the pressurized fluid from the selected vessel through the conduit to the selected receiving tank without using mechanical compression, electric power, or other external utilities, thereby resulting in an increasing pressure in the selected receiving tank and a decreasing pressure in the selected vessel from which the pressurized fluid is being transferred, the increasing pressure in the selected receiving tank being less than the pressure of the pressurized fluid in at least one other vessel; (f) measuring continuously a pressure differential between the increasing pressure in the selected receiving tank and the decreasing pressure in the selected vessel from which pressurized fluid is being transferred; (g) designating a limit value of the pressure differential at which a transfer of the pressurized fluid from the selected vessel is to be discontinued; (h) discontinuing the transfer of the pressurized fluid from the selected vessel when the limit value is reached; (i) selecting another vessel presently containing a quantity of the pressurized fluid at a pressure greater than the present pressure of the pressurized fluid in the selected receiving tank; (j) transferring at least a portion of another quantity of the pressurized fluid from the another selected vessel through the conduit to the selected receiving tank without using mechanical compression, electrical power, or other external utilities; (k) repeating steps (d) through (j) until the selected receiving tank is filled with pressurized fluid at a desired filled pressure; and disengaging the first end of the conduit from fluid communication with the selected receiving tank.
A fifth embodiment of the method is similar to the fourth embodiment of the method, but includes the following additional steps; (m) selecting another receiving tank to receive the pressurized fluid; (n) repeating steps (c) through (n) until the pressurized fluid can no longer be delivered from the self-powered station to the last selected receiving tank without using mechanical compression, electric power, or other external utilities.
A sixth embodiment of the method is similar to the fifth embodiment but includes the additional steps of: (o) refilling at least two of the n+1 vessels with the pressurized fluid, each refilled vessel containing a quantity of the pressurized fluid having a pressure which decreases as the quantity decreases; and (p) repeating steps (b) through (p).
The present invention also includes a method for controlling a rate of delivery of a pressurized fluid from a storage vessel to a receiving tank through a conduit in fluid communication with the storage vessel and the receiving tank. The method includes two steps. The first step is to establish a predetermined rate of pressure rise to be maintained during a predetermined time period for filling of the receiving rank with the pressurized fluid. The second step is to maintain the predetermined rate of pressure rise during filling of the receiving tank with the pressurized fluid during the predetermined time period.
There are several variations of the method for controlling the rate of delivery of the pressurized fluid. In one variant, the step of establishing a predetermined rate of pressure rise includes multiple sub-steps. The first sub-step is to generate an electric signal convertible to a low pressure gas signal. The second sub-step is to amplify the low pressure gas signal. The third sub-step is to control a fill pressure in the receiving tank.
In another variation, the step of maintaining the predetermined rate of pressure rise includes multiple sub-steps. The first sub-step is to provide a pressure control device in communication with the conduit or another conduit through which the pressurized fluid flows at an actual pressure before entering the receiving tank, the pressure control device adapted to increase or decrease the actual pressure of the pressurized fluid. The second sub-step is to calculate periodically a rate of pressure rise over time. The third sub-step is to command the pressure control device to decease the actual pressure when the rate of pressure rise is greater than the established predetermined rate of pressure rise, and to increase the actual pressure when the rate of pressure rise is less than the established predetermined rate of pressure rise.
In another variation of the method, the rate of delivery is controlled as a function of either a percentage of a designated target pressure already achieved, or a percentage of a designated target pressure yet to be achieved during a remaining portion of the predetermined time period. In a variant of this variation, the function is linear. In another variant, the function is geometric. In yet another variant, the receiving tank has an instantaneous thermodynamic state and the function varies over time with any changes in the instantaneous thermodynamic state to provide an optimal rate of fill.
Another embodiment is a method for controlling a rate of delivery of a pressurized hydrogen gas at 5,000 psig or greater from at least one storage vessel to a hydrogen-powered vehicle fuel storage tank through a conduit in fluid communication with the at least one storage vessel and the hydrogen-powered vehicle fuel storage tank. This embodiment includes multiple steps. The first step is to establish a predetermined rate of pressure rise to be maintained during a predetermined time period for filling of the hydrogen-powered vehicle fuel storage tank with the pressurized hydrogen gas. This first step includes several substeps. The first sub-step is to generate an electric signal convertible to a low pressure gas signal. The second sub-step is to amplify the low pressure gas signal. The third substep is to control a fill pressure in the hydrogen-powered vehicle fuel storage tank. The second step of the method is to maintain the predetermined rate of pressure rise during filling of the hydrogen-powered vehicle fuel storage tank with the pressurized hydrogen gas during the predetermined time period. This second step includes several sub-steps. The first sub-step is to provide a pressure control device in communication with the conduit or another conduit through which the pressurized hydrogen gas flows at an actual pressure before entering the hydrogen-powered vehicle fuel storage tank, the pressure control device adapted to increase or decrease the actual pressure of the pressurized hydrogen gas. The second sub-step is to calculate periodically a rate of pressure rise over time. The third sub-step is to command the pressure control device to decrease the actual pressure when the rate of pressure rise is greater than the established predetermined rate of pressure rise, and to increase the actual pressure when the rate of pressure rise is less than the predetermined rate of pressure rise. In this embodiment, the rate of delivery is controlled as a function of either a percentage of a designated target pressure already achieved or a percentage of a designated target pressure yet to be achieved during a remaining portion of the predetermined time period.